The present invention relates to electronic signal processing circuits for processing a plurality of signals concurrently, and more particularly, to a monolithic integrated circuit capable of processing concurrently such a plurality of signals formed as discrete data samples through manipulating such data samples and entities derived therefrom in accord with selected algorithms.
There are various systems requiring therein the manipulation of information and in which additional information is acquired from a multiplicity of information sources operating concurrently. The information acquired from each of these sources may constitute a separate signal from each source resulting in the number of signals for processing being equal to the number of concurrently operating sources present or, in some cases, the information from some of the sources may be somehow grouped yielding a reduced number of information signals for manipulation.
A common system of this nature is an image processing system in which an image of some scene of interest is provided on a sensing surface, this surface comprising of a number of individual radiation detectors to each indicate the amount of radiation occurring in that part of the image falling on that radiation detector. Such radiation may be electromagnetic in the visible light portion or infared portion of the spectrum, for instance, and the radiation detector would then be a photodetector. Typically, each radiation detector provides a voltage or current output signal over time which contains the information as to the amount of electromagnetic radiation falling on that photodetector over time. So, the signals of all the photodetectors taken together carry the information as to what radiation amount is occurring in the image portions falling across all those photodetectors at each point in time during which the image is provided on these photodetectors. This is equivalent to stating that these photodetector voltage, or current, output signals carry (i) the information as to what is in the field of view available to the system at any instant of time as it is reduced to an image by other portions of the system, and the (ii) information as to the changes occurring within this field of view over time.
As a result, the information in these photodetector output signals concerning the system field of view over time are often desired to be processed (i) to improve the image effectively obtained therefrom by removing unwanted aspects therefrom due to any system limitations or due to any adverse viewing conditions, or by making more prominent some of the features therein, or the processing is desired (ii) to provide a set of signals containing more specific information derived from features or occurrences in the system field of view. Thus, some of the goals of such signal processing can be to provide image feature enhancement, to provide reductions in the bandwidth of the signals carrying the image information, to find which portions of the features in the image are due to various parts of the electromagnetic radiation spectrum, to provide image feature cueing by feature type, to provide image feature motion detection and tracking thereof, etc.
A number of signal processing algorithms have been found which can be used to provide such image improvement or image information derivation. These algorithms are, in turn, a series of steps where each step is some basic mathematical or logical operation. If the information in the radiation detector signals is sampled so as to provide a discrete time or sampled data signal, these mathematical operations can be performed as a series of arithmetical and logic steps. Thus, a suitable signal processor must be able to perform a series of mathematical operations, and in the case of discrete time or sample data systems, these operations to be performed by such a signal processor will be a series of arithmetical or logic steps or both.
However, the amount of information contained in a set of signals obtained from a number of concurrently operating information sources, such as photodetectors in an optical image sensor, can be very great over some period of time. In an image sensor, for instance, there may be thousands of separate radiation detectors each providing an output signal which may lead to on the order of thirty million data samples in a second, or more, being provided by the image sensor. Furthermore, the use of various signal processing algorithms to manipulate this image sensor data to provide desired image improvements or to derive information, or both, can lead to requiring on the order of between five hundred million and a billion basic arithmetical or logic steps each second in the signal processor.
Providing these many basic operations in a second by use of a conventional digital computer as the signal processor, operating in serial fashion on the radiation detector signals, one after the other, is very difficult without resort to a large and expensive, very rapidly operating digital computer arrangement. Such computers are available for some purposes, but are quite impractical in many signal processing circumstances. For instance, an image sensor and signal processing system for operation in a space satellite or in an airplane must be small in size and low in power consumption while still providing substantial signal processing capability at a reasonable cost. Also, to yield a reasonably useful and effective overall system at a reasonable system cost, the signal processor portion of a system must often be capable of being directed to perform a changing set of algorithms as the applications for the system in question change and as the technology of signal processing advances.
An alternative manner in which to process such a set of signals at the required rates, and yet reduce the rapidity that a signal processor must perform any one basic arithmetical or logic operation, is to operate on the signals from the radiation detectors concurrently, i.e. in parallel, rather than acting on the signals one after the other in serial fashion. If done in a conventional digital computer arrangement provided to serve as the signal processor, this processing manner can reduce the capability required in an individual computer in the arrangement from that required of a digital computer operating on the signals in serial fashion, but this processing manner also increases the number of digital computers required to the point of one digital computer for each radiation detector signal or for each small group of such signals. Thus, while the capability requirement for each conventional digital computer in performing basic operations is eased in this manner, the power consumption, cost and size of a signal processor comprising such an arrangement of conventional digital computers is likely to substantially increase. Thus, a desirable signal processor would have a capability of processing the information source signals concurrently, but without requiring undue power consumption, cost or size.